Core box



T. H. OSTER Sept. 17, 1963 CORE BOX 3 Sheets-Sheet 1 Filed Jan. 3, 1961 INVENTOR.

R E s o H S A M o H T Sept. 17, 1963 Filed Jan. 5, 1961 T. H. OSTER CORE BOX 3 Sheets-Sheet 2 FIG. 4

THOMAS H. OSTER INVENTOR.

ATTORNEYS p 1953 T. H. OSTER 3,103,716

CORE BOX Filed Jan. 5, 1961 3 Sheets-Sheet 5 fl/7721 l/////// FIG. 5

+HOMAS H. OSTER INVENTOR.

RNEYS United States Patent 3,103,716 CORE BUX Thomas H. (Ester, Dearborn, Mich, assignor to Ford Motor Umnpany, Dear-born, Mich, a corporation of Delaware Filed Jan. 3, 1961, Ser. No. 80,121 6 (Jlaims. (Cl. 22-13) faotorily compacted core, a technique called core blowing is conventionally utilized. Core materials suspended in a stream of air enter the cavity at high velocity through blow holes. The air is exhausted to the atmosphere through vents in the core box which are arranged so that the core material will be trapped in the core box cavity while the air is permitted to escape from the core box.

Core boxes are usually made of two complementary mold sections that are superimposed upon each other. High pneumatic pressures required to transport and compact the core mixture results in some air being forced out between the edges of the assembled core box in addition to the air which is exhausted through the vents provided -for that purpose. As the air escapes, some of the core mixture is unavoidably carried out with the air causing considerable abrasive action on the surfaces of the mold section.

Mechanical seals between .the complementary mold sections of the core box have proven quite unsatisfactory. This is due to the requirement of accurately aligning the sections of the core box to assure the maintenance of a tight seal.

To prevent sand cutting due to air and sand leaking from the edges of the upper and lower sections at the parting plane of a core box, an air seal has been incorporated in the core box of this invent-ion. By introducing clean air along the periphery of the mating edges of the core box sections while the core is being blown, a tight seal can be achieved.

It is an object of this invention to reduce or eliminate the pressure diiierential between the interior and exterior of the core box which tend to cause sand and air leaks.

A further object of this invention is to provide a seal for a core box which is economical, highly durable, and efiicient in use.

Other objects and advantages of this invention will become more apparent as this description proceeds, particularly when considered in connection with the accompanying drawings wherein:

FIGURE 1 is an oblique plan view of a section of a core box showing a series of apertures in the edge of the section which surrounds the mold cavity;

FIGURE 2 is a partial sectional view taken along line 2-2. of FIGURE 1;

FIGURE 3 is an oblique plan view of a section of the core box showing a groove along the periphery of the edge of the section;

FIGURE 4 is a partial sectional view taken along line 4-4 of FIGURE 3;

FIGURE 5 is a partial sectional view through the upper and lower sections of an assembled core box of a third embodiment of this invention depicting the grooves in both sections superimposed to form a passageway;

FIGURE -6 is an oblique plan view of a section of a core box of a tourth embodiment of this invention show- 3,103,716 Patented Sept. 17, 1963 ice ing fanshaped slots along the peripheral edge of the section; and,

FIGURE 7 is a partial sectional view taken along line 7-7 of FIGURE 6. I

In FIGURE 1 is seen a'section 11 of a core box com prising a base 12 surrounded by side walls 13. In the center of base 12. is seen a core cavity 14 in the shape of a desired core. An edge 15 surrounds the core cavity 14 which is juxtaposed withthe edge of a complementary section (not shown) when the core box is assembled. The edges of both sections of the core box lie on the parting plane of the core box. Guide pins 16' facilitate the alignment of the sect-ion 11 with the complementarysection of the core box during the assembly to form a mold for the construction of the core.

Core materials suspended in the air are rammed by pneumatic pressure into the core cavity 14 through a blow hole 17. Vents 18 for the escape of air from the core cavity 14- are provided on the peripheral surface of the cavity 14. The location of the vents 18 is selected to provide for an effective escape of air without disturbing the core being formed. 7

In the first embodiment of this invention as seen in FIGURE 1, holes 19 are provided in one of the mating edges of the core box. Clean air is blown into the holes 19 through a conduit distribution line 20 which is completely contained in the base 12 of the section 11 as seen in FIGURE 2. An inlet tube 21 anda fitting 22 provide a connection for a hose which places the air distribution line 2!) in communication with an external air pressure source (not shown).

The holes 19, which may be of any configuration, sur round the periphery of the mold cavity 14 and are spaced to provide a relatively uniform distribution of air along the mating edges of the upper and lower sections when the core box is assembled to prevent leakage of air and sand from the core cavity 14- to the atmosphere.-

In a second embodiment of this invention as shown in FIGURE 3, a groove 23 is provided along a planar peripheral edge 24 of a section 25 of a core box. As seen in FIGURE 4, a plurality of vertical conduits 26 are provided to place the -groove23 in communication with a conduit distribution line 27 which is connected to an external air pressure source (not shown) through an inlet tube 28 and a fitting 29. V

In FIGURE 5 is seen a partial section of an upper section 39 assembled with a lower section 31 of a core box 32 which illustrates a third embodiment of this invention. The core cavity 33 is defined by the assembled com plernentary upper section 39 and lower section 31 of the core box 32. A groove 34 located in a planar pe-' ripheral edge 35 of the upper'section 3t) is aligned with a second groove 36 located in a peripheral edge 37 of the lower section 31 to form a passageway -for pressurized air when the core box32 is assembled. The air distribu-' tion system in the-lower section 31 as seen infFIGURE 5 may be similar in construction to the air distribution system of the heretofore mentioned embodiments of this invention.

It is to be understood that the air distribution system may be located in the upper 39 or lower section 3 1 or in both sections of the core box 32.

A fourth embodiment of this invention is shown in FIGURE 6. In this embodiment, a series of relatively small circular holes 3'8 are placed in a planar peripheral edge 39 of a section 4t} of a core box. An air distribution system, similar to the air distribution system of the previous embodiment of this invention is provided to distribute lclean air to each hole 38. To achieve a continuous uniform air seal between the sections of an assembled core box, a fan shaped slot 41 is cut into the 3 openings of each hole 38 best seen in the partial sectional view of FIGURE 7. The base 42 of each fan shaped slot 41 is to lie on the surface of the peripheral edge 39 along a parting plane of the core box.

It is to be understood that a series of holes or grooves or a combination of holes and grooves may be provided in either the upper or lower section or both sections of the core box to achieve a satisfactory air seal.

When core material suspended in air is blown into a core cavity, most of the air will be exhausted through the vents provided for that purpose. Some air and sand will escape across the edges of the assembled upper and lower sections along the parting plane of the core box. By introducing pressurized clean air along the mating edges of the core box sections and uniformly distributing this air along the entire periphery of the core box, an air seal is formed between the sections to eliminate or reduce air leakage from the core cavity. Clean air for the air seal may be provided to the core box by a conduit directly connected to the core blowing machines air source so that the air seal is made operative simultaneously with the blowing of the core. At times it may be advisable to provide an independent external air source for the core box seal to permit the regulation of air pressure to the air seal.

The introduction of clean air to the seal will reduce the pressure differential between the core cavity and the atmosphere to lessen the leakage of air and sand from the core box. To eliminate any leakage of air and sand from the core cavity, the pressure of the clean air introduced at the seal is to be at least equal to the air pressure employed to move the core material to the core cavity of the core box. A slightly higher air pressure at the seal will result in clean air being forced into the core cavity to keep the surfaces of the mating edges of the assembled core box free of any loose material.

I claim:

1. In a core box construction including complementary sections forming a core cavity, said complementary sections having mating edges juxtaposed at a parting plane of said core box, a blow hole directed into said cavity, at least one vent from said cavity, a groove in one of said mating edges, and an air pressure source in communication with said groove, said groove being adapted to form an air seal between said complementary sections when said air pressure source is activated.

2. In a core box construction including complementary sections forming a core cavity, said complementary sections having peripheral mating edges juxtaposed at a parting plane of said core box, a blowhole directed into said cavity, a vent from said cavity, a peripheral groove in each of said mating edges lying on the parting plane of said core box, said groove forming a passageway when said mating edges are juxtaposed at said parting plane, and an air distribution means in communication with at least one of said grooves, said air distribution means adapted to uniformly distribute air to said passageway formed by said grooves.

3. In a core box construction including complementary sections forming a core cavity, said complementary sections having peripheral mating edges juxtaposed at a parting plane of said core box, a blow hole directed into said cavity, an atmospheric vent from said cavity, a peripheral groove in one of said edges lying on said parting plane, an air distribution means in communication with said groove, and an air pressure source in communication with said air distributing means, said air distributing means distributing air from said air pressure source to said groove at a pressure at least equal to the air pressure in said cavities to form an air seal along the edges of said complementary sections.

4. In a core box construction including complementary sections forming a core cavity, said complementary sections having planar peripheral mating edges juxtaposed at a parting plane of said core box, a blow hole directed into said cavity, at atmospheric vent from said cavity, a plurality of holes in one of said planar peripheral edges, and an air distributing means in communication With said holes, said air distributing means adapted to uniformly distribute air to said holes and to form an air seal between the mating edges of said complementary sections.

5. In a core box construction including complementary sections forming a core cavity, said complementary sections having planar peripheral mating edges juxtaposed at a parting plane of said core box, a blow hole directed into said cavity, at least one atmospheric vent from said cavity, a plurality of holes in one of said edges lying on the parting plane of said core box, a fan shaped slot for each of said holes, the base of said fan shaped slots lying along the planar surface of one of said mating edges, and an air pressure source in communication with said holes, said air pressure source supplying air to said holes at a pressure at least equal to the air pressure in said cavity to from an air seal along the mating edges of said complementary sections.

6. A core box in association with a core blowing machine having an air pressure source comprising complementary sections forming a core cavity, said complementary sections having peripheral mating edges juxtaposed at a parting plane of said core box, a blow hole directed into said cavity, at least one atmospheric vent from said cavity, and air outlet means along said mating edges of said sections lying on the parting plane of said core box, said air outlet means in communication with said air pressure source adapted to form an air seal between said complementary sections when said core blowing machine is activated.

References Cited in the file of this patent UNITED STATES PATENTS 2,073,469 Fleisher Mar. 9, 1937 2,459,295 Skoog Jan. 18, 1949 2,800,690 Olson July 30, 1957 2,923,040 Goodwin Feb. 2, 1960 2,958,104 Ohse Nov. 1, 1960 FOREIGN PATENTS 907,614 Germany Mar. 25, 1954 

1. IN A CORE BOX CONSTRUCTION INCLUDING COMPLEMENTARY SECTIONS FORMING A CORE CAVITY, SAID COMPLEMENTARY SECTIONS HAVING MATING EDGES JUXTAPOSED AT A PARTING PLANE OF SAID CORE BOX, A BLOW HOLE DIRECTED INTO SAID CAVITY, AT LEAST ONE VENT FROM SAID CAVITY, A GROOVE IN ONE OF SAID MATING EDGES, AND AN AIR PRESSURE SOURCE IN COMMUNICATION WITH SAID GROOVE, SAID GROOVE BEING ADAPTED TO FORM AN AIR SEAL BETWEEN SAID COMPLEMENTARY SECTIONS WHEN SAID AIR PRESSURE SOURCE IS ACTIVATED. 